1. Field of the Invention
The present invention relates to a recording tape cartridge used primarily in a computer and the like as a recording/playback medium, in which recording tape such as magnetic tape is wound around a single reel and accommodated inside a casing.
2. Description of the Related Art
Conventionally, a recording tape cartridge is known to be used as a data recording/playback medium for a computer and the like, where recording tape such as magnetic tape is wound around a single reel. The reel is rotatably accommodated inside the casing of the cartridge. An opening is formed in the casing of the recording tape cartridge for pulling out the recording tape, and there are cartridges provided with a door that opens and closes that opening.
Known styles of doors include sliding-type and turnable-type doors. Ordinarily, the door is urged towards the closed direction of the opening with a urging means such as a coiled spring or a torsion spring. In the case of a turnable door, for example, a torsion spring is used as the urging means. In light of compatibility factors between the torsion spring and the casing of the cartridge, the torsion spring is often arranged between the bottom end surface of the door and the bottom inner surface of the casing. That is, after the coil portion of the torsion spring is inserted and fitted on a support axis provided to protrude from the casing, the region that becomes the turning support point for the door is inserted and fit through (see, for example, Japanese Patent Application Laid Open No. 2000-11591).